Technote 127: Leveled Acoustic Output, PDF only. To test acoustic input devices like microphones and hearing aids, users typically want to stimulate the device under test (DUT) with an acoustic signal at a specified sound pressure level (SPL). In addition, to measure the frequency response of acoustic devices, it is desirable to create a sound field that has the same sound pressure level over a wide range of frequencies. This is sometimes referred to as "leveled acoustic output."
